And her fellow Conservative, Wales office minister David Jones, accused the presiding officer of partcipating in "guerrilla warfare".

The Wales Office is based in Whitehall in London, with another office in Cardiff, and is headed by the secretary of state for Wales.

It was set up in 1999 to ensure the smooth working of devolution, and is described as "Wales' voice in Westminster and Westminster's voice in Wales".

If you don't have a secretary of state for Wales batting for Wales then Wales's voice will be reduced and that is a very important factor.Peter Hain, Shadow Welsh Secretary

It previously handled the assembly's request for new law-making powers.

Following the Yes vote in last week's referendum, the assembly no longer needs parliament's approval before passing legislation in the 20 policy fields that are devolved to it, such as health and education.

And on Sunday Lord Elis-Thomas said the sooner the department was gone "the better".

But on Monday Mr Hain commented: "It will always be necessary to have a secretary of state for Wales.

"Whether it's configured in precisely the same way is another matter but there will always be a need. It's defined in statute. There's various responsibilities that the post needs to undertake."

Mr Hain conceded that as a result of the referendum, the nature of the post would change.

"It may be that there needs to be a change in staffing levels. It will be that there needs to be a change in focus," he said.

"But you need somebody around the Cabinet table tapping the shoulders of Cabinet colleagues to say: 'What about the Welsh budget?'

"If you don't have a secretary of state for Wales batting for Wales then Wales's voice will be reduced and that is a very important factor."

Mr Hain earlier accused Lord Elis-Thomas of "acting above his pay grade" and of being "out of touch with the people of Wales."

Image caption
Cheryl Gillan said Welsh people still wanted 'connectivity' with Westminster

Lord Elis-Thomas told the Sunday Supplement programme: "Now that the responsibility of ministers for administration of policy and indeed for legislation is now here, it makes more sense for us to be organised in a proper inter-governmental and inter-parliamentary way.

"That is assembly to Westminster, government to government.

"That would mean, I think, winding up the Wales Office and as far as I'm concerned the sooner the better.

"I would like to start operating in the new way after the 5th May election."

Welsh Secretary Cheryl Gillan said: "He's singing to a separatist tune and I don't think that's what the people of Wales want or the businesses who invest in Wales.

"They don't want separatism, they want that confidence and maturity to allow Welsh laws to be made closer to the people of Wales but they also want that connectiveness to the rest of the United Kingdom."

Speaking on BBC Radio Wales on Monday, Wales Office minister David Jones said that as a nationalist, Lord Elis-Thomas had spent his career trying to take Wales out of the union of the UK and create an independent Wales.

'Fighting their corner'

"It therefore benefits him and his party to undermine the British state," said Mr Jones. "What he was doing yesterday was really part of this process. He has, if you like, declared guerilla warfare upon the British state."

Mr Jones added: "It's vitally important that the Welsh people should have a voice in government in Whitehall fighting their corner, and that is why I believe that the Welsh Office will continue."

Former Labour Welsh Secretary Ron Davies, now a Plaid Cymru councillor, said constitutional reform had been on the agenda for a long time and Wales having primary law-making powers would speed up that process.

But he told BBC Wales a figurehead was still needed and believed there would eventually be a secretary for the regions who would look after Wales, Northern Ireland and Scotland.